Selective system.



*Nb. 824,20.6-.- PATENTED JUNE'ZG. 1906.

A- R D-s SELECTIVE SYS EM,

APPLICATION FILED JAN.23. 1905.

2*SHEETS-SHEET 1.

PATENTED JUNE 26, 1906: s. A. REED. SELECTIVE SYSTEM. APPLICATION FILED JAN. 23 1905.

2 SHEETS-SHEET z.

I Inventor:

UNITED STATES PATENT OFFICE.

SYLVANUS ALBERT REED, OF. NEW YORK, N. Y.

SELECTIVE SYSTEM.

Specification of Letters Patent.

Patented June 26 1906.

Application filed January 23. 1905. Serial No 242,311.

To all whom it may concern:

Be it known that I, SYLvANUs ALBERr REED, a citizen of the U: ted States, residing in the city, county, and State of New York, have invented certain new and useful Iniprovements in Selective Systems, of which the following is a full, clear, and true specification.

' My invention relates to improvements in systems of electrical selective control capable of application with advantage to a variety of uses, and involves certain prlnciples of operasignal-receiving annunciators and is otherw1se capable of application to open-circuit lines.

The principle of the invention and several modes of applying the same are hereinafter fully disclosed, and more particularly pointed out in the accompanying claims.

Referring to the accompanying drawings,

Figures 1 and 2 are diagrammatic representa tions of the principle of my invention applied to simple selective use. Fig. 3 is. an application of the same to an ordinary commonbattery party-line. Fig. 4 is a modification in the means of potential control. Fig; 5 is a further modification; Fig. 6 a further application of the invention.

Referring to Fig. 1, the reference character A represents signal-receiving annunciator mechanism in diagram, the elements A A whereof are of similar construction, but arranged to be operated, respectively, by currents of opposite polarity, this eflect being produced by appropriately stopping the movable indices thereof, as shown, so that the one, A, is free to swing to the left, and the other, A to the right. The said indices arealso held against their back-stops by a yielding force of definite tension, such as a small coil-spring which is applied to the indices so as to oppose their operation except by a sufficiently-strong current of the proper polarity. The annunciator mechanism is connected between the conductors G and M in series relation with a translating device or condenser C, which interrupts the conductive continuity said source. and the source constitute a means for impressof the circuit, and the two conductors lead,

respectively, to one poleof the source of cur-- 7 rent S and to; a movable contact T, which is f adapted to have sliding successive contact with the series of contact-plates a b c, &c., of a rheostat R, connected with the poles of the The rheostat, sliding contact,

ing current upon the circuit which will bring about in the annunciator mechanism A an alternating current the'composing opposite currents of which are relatively differentiated to be either superior or inferior in'motoreffeet to the tension of the above-mentioned yielding force, and the said means is capable of manipulation so that either the plus or; the minus currents will be superior, thereby tenabling a selection to be made between the two elements A and A which, as above, ex.-

plained, are respectively arranged to respond tocurrents of opposite direction. This manipulation may be explained as. follows: If the contact T be first placed upon the, rheostat Rat the plate a, the condenser C, becomes charged at a difference of potential substantially equal to the difference between the opposite ends of the rheostat, and the momentary rush of current which ensues through the annunciator mechanism A will have a definite polarity and a suflicient strength to overcome the bias tension of whichever index is arranged to respond to that polarity-say, for example, A. If the contact just made should be broken and rovided the line M has some capacity, it is 0 vione that a current of reverse polarity would 5 ensue in the annunciator mechanism, which might actuate the index of the other element A and even if the line has but a slight capacity it is plain that before we can repeat the operation of A to make an indefinite succession of strokes we must first wholly or. partly discharge the condenser. If this is done. by applying T directly to '11, the reverse current. ensuing at discharge would actuate A; but if, on the other hand, the contact T he slid along the rheostat successively over the plates 5 c d, &c.,toward the opposite pole pf the battery to the last plate '5 thechargej gin the condenser-surfaces will become gradually releasedthat is to say, the previously-ex.-

isting difference ofpotenti-al will be removed or approximately equalized at a rate more gradual than its establishment and. thereverse current which ensueswill be of. weak strength compared to theotherand incapa ble of 'operatiiig the index of A against its bias tension. Thus by repeatedly stroking the rhcostat upwardly inh similar manner the index of element A may be repeatedly actuated to the exclusion of the index of element Reversal of the direction of relaave movement between the contact and rheostat will in like manner effect the operation of A to the exclusion of A, because such reversal results in a gradual establishment of' the previous difference of potential between the opposed condenser-surfaces and an abrupt release, and the current corresponding with the establishment is insufficient to overcome the tension of. the spring of element A, while the abruptrelease effects an operative reverse-current for A The distinction between anabrupt and a gradual change in the ilifi'erence of potential between the opposed eondensensurfaces is that the latter is such a chan geas does not result in acumulative force onercoming- ,theresistance of the moving elemcnt ofthe annunciator-t'. (2., its bias tension, inertia, and. friction-while the abrupt change does result in a cumulative force which'does overcome the said resistance. instead of selecting A. or A by reversing the direction of relative movement between the contact and rheostat the same result may be secured by; reversing theconncctions of line conductorsG and M therewith or the polarity of the battery and continuing to stroke the rheostat 1n the-same direction. 1

i In, Fig. ,2 any arrangement of circuit is shownun which the conductors G and M are provided with a pole-changer P-for this purose. The elements A and A", which are ere SllOWHlll series with separate condensers,-,are, both capable of: selective operation 1 oLrelative".movement, for the ilfhstration herein I shall this figure,

by a'gradual establishment and abrupt removfialzof the difference of potential 1n the condenscrs, OPVICB versa, the difl erence 1n direction of. theoperating-currentfor each annunciator element being effected by the inversionof theyconnect-ions. While this method ofzQntroluise-in some respects more simple thanlthe methodby reversal of tllGCllIGCtlOIl urposes of procee to describe the-lattenmethod as a plied to practical use, it;being" understood, 0 course, that in so far as-ithe'sjelective effect in the circuit is concerned theatwo methods are the same, and in .islegged to ground, the-legs of. each air con taming-polarized op ositely-biase electric annnnciators orw'telep one-ringers '1, 2, 3, or

4 in series, respectively, with condensers C, C C or C, the tension of the bias springs 5 being set to resist the inferior currents of the alternating current which will traverse them. Theline conductors terminate at the o crating-station in the usual line-jacks, whic may be connected in the ordinary manner with switching mechanism comprising a suitable number of keys for connecting either line conductor to the sel'ectiveringing apparatus to effect the selection. p

The means for impressin appropriate current upon the line is-shown herein as comprising a pair of rheostats R and Rfl'each similar to that shown in the precedin figures, except that they are made in ring orm to permit of relative rotation between them and their cooperating contact-brushes B and B thereby mechanically producing a similar cf feet to the stroking of the rheostat above ex' plained. The rheostats are stationary and connected in opposite sense between the two poles of a source S- of direct current, so that the internal brushes B and B may both rotate in the same direction within them, and yet produce with one rheostat the effect of a gradual establishment of the required difference of potential and with the other a radual release of the same. One pole 0% the source-for example, the negative pole-is grounded. The brush B is connected by wire E to the keysK and K, by means of which it may be connected to either line 0011- ductor-M. or N, and the brush B is similarly oined by wire E to the keys K and K for a like connection; The arrangement of the rheostats as above described permits of their being arranged com actly side by side and the rotary brushes isposed upon the same interior shaft, which latter may be driven at a substantially constant speed by a motor or otherwise. The speed of the shaft which controls the rate of establishment or dises-' tablishme'nt of the difference of potential be tween the opposed condenser-surfaces is de-' sion of the bias springs of the annunciators, provided the inductance in the circuit is low, it being necessary that the rate of change be less than that which will produce an, operative current; but this is not a delicate matter,

and the brushes may rotate at a rate of speed high enough to roduce a rapid oscillation'of: the selected bel -hammer without producing by a good margin an-inferiorcu'rrent'capable of actuating a non-selected ringer. In cases where the circuit contains considerable inductance it is found in practice that very rapid changing of the impressed current is apt to distort the wave characteristic to-such" an extent as to call for a compensating adjustment of some kind for preserving in the condensers the above-described. effect of a:

gradual charging and abruptdischarging, or-

vice versa. It will of course be understood ICC 'termined principally in relation to the tenthat the annunciatorsi,2, 3, and 4 are each presumed to be located at'ene'of the several substations of the line and that each such substation is provided with the usual talklllgrbl'ldge and other telephone ap1purte.

w or

nances, which it is not necessary to s describe, the present drawings being essentially diagrammaticj The central office is supplied with the usual means for interconits normal open circuit or unused condition and the rotary brushes constantly driven either one of'the annunci'ators 1, 2, 3, or 4 may be selected and rung by the operating of the'-'-- corresponding key K, K K or K Thus" by the pressure of key K the line M is donnected by the 'wire E to the rotating ".fb rush B'iwhich travels in the direction of the arrowtfrom the positive end of the rheostat over-the successive rheostat contact-plates to J the negative end and from thence abruptly-to the;positive-again. Since one pole of the sou1'ce of current S, as well as the annunciaftorbranches' ofthe line, are .all grounded, it will be recognized that depression of key K has brou ht about the same circuit relations as are e bited in Fig; 1, and the transit of the rotary brush B abruptly from the negative to the positive contact-plate and around through the resistance to the negative plate again corresponds to the stroking of the rheostat of Fig. 1 in an upward' direction,

with the result that annunciator 1 is repeat- I edly operated by the abrupt establishment of gradually-removed differences of potential, annunciator 2. remaining unoperated, because it is oppositely biased to respond to superior currents of an opposite direction. Annunciators 3 and 4 being connected in a practically isolated v line are not affected. When key K is depressed, the line conductor M is joined by wire E to the rotary brush B, and the efiect is otherwise similar. to that just described, save for the fact that this brush travels from the positive end oi' the rheostat abruptly to the negative end and then around through the resistance back to the positive end-that istosay, the difference of poten, tialin the condensers on line M is now gradually established and abruptly removed, corresponding to a stroking oftherheotstat of Fig. 1 in a downward direction. The same ei'iaration may obviously be carried on with the line N by keys K and K". p In order to provide against the contingency of one of the subscribers of the line removing. his receiver from the hook during the ringing of oneof the lines and the consequent confusion which wouldbe caused by the interconnection of the two line conductors, a short-circuit branch 6 is provided to the ground, to be controlled by each of the keys K",'&ci, so that when any key-for example, Kis operated toconnect the line M with the operating apparatus it at the same time connects the other line N directly to the ground,

thereby short-circuiting the ringing im-' pulses whichmight otherwise cross the subscribers closed talking-bridge'and'enter the annunciators 3 and 4.

The rheostat shown herein as comprised of a series of insulated contact-plates succes-- 'sively connected by resistance-coils is constructed that the jump in resistance from one plate to another is so slight that although more or less sudden in occurrence the change of potential difierence which it effects in the translating devices is inefiectual. tact-brushes should be of ample contacting area to bridge the insulation between. the plates, so that at no time inits transit will the condenser-circuit be broken until the end of the rheostat is reached, at which point the insulation may be extra wide for purposely The con- I producinga break. Instead'of the-structural wire resistance-rheostat indicated the same can obviously be supplanted by a homogeneous strip of'some diflicultly-conducting material and the contact, which could then be of'any area, could travel upon it. In this case it is obvious that the *sti-blishment and disestablishment of the condensercharges would be. still. more gradual than in the form'shown. Furthermore and inasmuch as the opposed condenser-surfaces in of the battery. In this case the contact T is double and its two insulated components aremutually connected through appropriate resistance, so as to prevent the short-circuiting of adjacent cells as the contact passes over them. Obviously this form of control can be adapted to circular arrangement, as in Fig. 3, so that the contact T may become a rotary double-contact brush.

As a further modification and simplification of the means for impressing appropriate current upon the line a driven current generator or generators may be employed instead of the batteries and sliding contacts. Such generator, however, must be properly constructed or adjusted with respect to the con- TIC) ditions present in the line to produce the ef,

feet, above fully described, of an abrupt establishment andfgradual removal of; the con denser charges, or vice 'versa, and either onev generator may be employed with Ine'ansfo f rangement in .its application to a four-party line is outlined in Fig. 5, wherein one generator is ad .usted to eliect an abrupt establ shment and gradual removal of the condenser charges, and the other the reverse, with appropriate connections, as in F 1g. 3,

for connecting either generator to either line conductor. The wave form of the current impressed upon the circuit by these generators under simple line conditions will be about as shown by X X in Fig. 5, or it may be an alternating current similar to that indicated by Y Y in the same figure; but in case of great inductance in the line or of high frequency of the impressed current, or both, it will necessarily assume a quite different form, as already suggested, which may not be as symmetric as shown in Fig. 5.

A further application of the invention is shown in Fig. '6, wherein the annunciators are bridged in series with condensers between the line eoi nluctors and are capable "of selection in the same manner-as was described with reference to Fig. 1, the connections being clearly indicated in the drawings. With this arrangement a two-party selective line is produced wherein the line conductors are conductively isolated from each other, and either of the polarized oppositely-biascd annunciaters in the bridges -i n.ay be operated with the same apparent ei'iccfas though. operated by a pulsating current in a 'conductively-c nitinuous line. p

v The in'ventionis capable of" various other modifications to adaot it to familiar. tele phone construction; but inasmuch as fea tures of the proportions and adiustments of the various parts to proda 'ief most cilici'cnt results are matters dependingehtirely onthe conditions to be found in the particu lar system to which they are appliedthe same must be left to the judgment and skill of the practical electrician. I

ll aving described my invention, whatl claim, and desire to secure by United States Letters Patent, is

1. A signaling system, comprising a circuit and two imiositely-biased electromagnetic anmmciators connected in multiple relation therein and each-in series with a condenser,

in combination with a means of impressing current upon said circuit to charge and discharge the condenser-surlaccs abruptly and gradually, the current in the annunciators due to the abrupt charging or discharging being effectual to overcome the bias tension thereof and that due to the gradual charging or discharging being ineliectualfor that purpose, and means for reversing the direction through the annunciators of the current due to the abrupt charging or discharging 2. In a selective system, a circuit including two o'ppositely-biased electromagnets and a translating device interrupting the conduct-' ive continuity of said circuit, in combination. with means for selectively impressing current on the circuit through said translatin device to produce in the electromagnets an a ternating current whereof the currents of opposite polarity are relatively differentiated in motor effect, and means for selectively causing thecurrent of one polarity to be superior and the other to be inferior to'the bias tension of any elcetromagnet.

In a selective system, a circuit including signal-receivin annunciator mechanism arranged to be selectively. operated b currents of relatively opposite direction an rovidedwith. yielding means-opposing sue operation, and a condenser or condensers in series with said mechanism, in combination with means i or charging and dischar ing the condensers to produce in said mec hanism relatively dili'crentiated currents of alternatel opposite direction and means for selective y causing the current of. one direction to be supcrior and the other to be inferior, in motor efl'ect, to the tension of said yielding means.

.4. In a selective system, a circuit including two polarized eiectromagnets, oppositely biased with. respect to currentof one direc-- 5 tion, condensers in series relation therewith and means for impressing current upon said circuit adapted to change the .(lfllGIGDCG of potential between opposed condenser-surfaces at a rate of change predetermined to I00 correspond to a strength of current'in said electromagnets which is ineii'ectual to overcome the tensions of their respective biases.

in a selective systenna circuit including two polarized electromagnetic annunciators 105 oppositely biased with respect to current of one direction, condensers in series relation. therewith and means for impressing current upon the circuit adapted and controlled tochange the di'fi'erence of potential between no opposed condenser-suriaces at rates otphange predetermined to correspond to a strength of current in said annunciators which is alternately eii'ectual and ineffectual to overcome the bias tensions thereof.

6. A selective system comprising a source of current, signal-receiving annunciator mechanism arranged to be selectively operated by currents of opposite direction and. provided with. yielding means opposing such, 12o operation and condenser-surfaees in series relation with said mechanism, in combina tion with switching mechanism controlling the current from said source to produce a charge of definite polarity upon either of the 125 opposed condenser-surfaces and means for establishing or releasing such charge at a rate that will correspond to current in thesaid mechanism of insuthcient strength to evercome the tension of the said yieldingineans. 1 0

'7. In a selective telephone-signaling system, two oppositely-biased polarized telephone-ringers and a source of current with connections for operating the same, comprising a translating device in series with each ringer adapted for translating the current energy of the said source into alternating.

currents for said ringers, in combin ation with means controlling the current energy supplied to said devices for causing either the plus or minus currents effect-ed thereby to e inferior in strength to the bias tensions of said ringers.

8. A selective telephone signaling system,

the opposed condenser-surfaces at a rate ofchange predetermined to correspond to a strength of current in said annunciators which is alternately effectual and ineffectual to overcome the bias tension of either of them.

9. A selective telephone signaling system comprising two line conductors with opencircuit subscribers apparatus bridged thereacross, a pair of polarized oppositely-biased annunciators legged from each conductor to a common conductor or ground, condensers in said legs in series with the annunciators, and a source of current, in combination with means for establishing or removing a difference of potential between the opposed condenser surfaces of either line conductor at such rate as will correspond to a strength of current in the annunciators insufficient to overcome the tension of their respective biases.

10. A selective system comprising a source of current and a rheostat connected between the poles thereof, annunciator mechanism arranged to be operated b currents of either polarity and provided with yielding means opposing such operation, condenser-surfaces in series relation to said mechanism and adapted to be connected in multiple relation to said rheostat, in combination with means for relatively shifting the point of communication between one oi the opposed condenser-surfaces and said rheostat to control the rate of change of the difference of potential between the said opposed condenser-sun faces.

1 1. A selective system comprising a source of current and a rheostat of-ring form connected between the poles thereof, two polar-L ized and oppositely-biased annunciators provided with condensers in series therewith, in combination with connections between the opposed condenser-surfaces respectively to one pole of the source of current and to a contact engaging said rheostat, the said contact and rheostat being adapted for relative rota tion whereby a difference of potential between the condenser-surfaces may be abruptly established and gradually removed or vice versa. j

12. In a selective system, a nag-form rhea ostat and relatively rotary contact-brush en-.

gaging the successive contacts thereof "and passing abruptly from one end of the same to the other, a source of current with its opposite poles connected respectively to the opposite ends of'said rheostat, and two polarized oppositely-biased annunciators in series with condensers connected-with said rheo-v stat and brush and capable of selective opera tion by the impulses produced thereby.

13. In a selective system, a pair of oppositely-biased polarized annunciators, and condensers in series relation therewith, in combination with means to operate said annunciators involving a potential gradient with contacts in connection with successive points thereon, and suitable connections between the above-mentioned parts .whereby the plus or minus currents from said condensers may be respectively caused to be 1nferior to the bias tensions of said annunciators.

14. The method .of selectively operating either of two oppositely-biased ringersin a condenser broken circuit, which consists in impressing current on said circuit to change the potential difference in the condensers thereof at a rate of change appropriate to produce a cumulative current-of sufiicientmotor effect in said ringers to overcome their bias tension, and at a rate of change corresponding to a current of opposite direetion therein insuflicient to overcome such tension, alternately, andcontrolling said roe pressed current to cause the currents of either direction in said ringers to be superior in mo .tor effect to the bias tension thereof.

.In testimony whereof I have signed my name to the specification in the presence of two subscribing witnesses. I

SYLVANUS ALBERT REED;

Witnesses:

H. G. KIMBALL, G. A. TAYLOR. 

